ABSTRACT
Amphiphiles form a variety of supramolecular structures such as aqueous and reverse micelles, monolayers, multibilayers, liposomes and vesicles. The interest and applications of these supramolecular structures have evolved from the purely academic use to liposome-based industries. The property of forming bilayers and bilayer-encompassed assemblies is not a unique feature of natural phospholipids but a general property of amphiphiles of appropriate structures. Bilayer-forming amphiphiles, with a variety of chemical structures, form vesicles or liposomes of a wide range of sizes and complexity. The simplest method of liposome preparation consists in the deposition of a film, obtained by evaporation of a solution of an amphiphile in an organic solvent, hydration with excess aqueous solution, and gentle or vigorous shaking. One of the observations exploring catalytic effects of vesicles prepared with synthetic amphiphiles was the study of the hydrolysis of p-nitrophenyl acetate and p-nitrophenyl palmitate catalyzed by the cholesteryl ester of imidazolecarboxylate in didodecyldimethylammonium bromide sonicated vesicles and hexadecyltrimethylammonium bromide micelles.
